KINGDOM ANIMALIA The Kingdom Animalia is the largest of the 5 Kingdoms in Domain Eukarya. Although the members of this

kingdom are very diverse, all are multicellular, eukaryotic and heterotrophic. They are further

characterized by having specialized cells and tissues for particular functions. All animals reproduce

sexually with simpler members being capable of asexual reproduction as well. This kingdom is

subdivided into 2 groups: Invertebrates and Vertebrates.

INVERTEBRATES - Animals Without Backbones

Animals that lack a backbone are called invertebrates. It is estimated that 97% of all species of animals are

invertebrates. With the exception of insects, most invertebrates are marine.

Phylum PORIFERA Example: SPONGES

Sponges are called porifera or “pore bearers” because of the pores on the

sides. They are among the simplest multicellular animals. They do not

have any tissues or organs. They are animals that are a complex bundle

of specialized cells Nearly all sponges are marine and all are sessile,

which means they live on the ocean bottom or attached to something and

come in many shapes and sizes so are described as asymmetrical.

The outer surface of a sponge is covered with

flat pore cells which allow water to enter.

Water is pumped into a larger canal lined

with collar cells (choanocytes) The cells

have a flagellum that creates currents and a

thin collar that traps food that is later

ingested and passed to specialized cells

(amoebocytes) for distribution. Water then

leaves through the osculum, a large opening

at the top of the sponge. Since the sponge

actively filters material out of the water to

eat they are known as filter feeders. As sponges grow larger they need support. Spicules are supporting

structures.

Sponges can reproduce asexually when branches or buds break off and grow into larger sponges.

Sponges can also reproduce sexually by producing egg or sperm. The sperm enters the sponge and

fertilizes the egg. The gametes are released directly into the water.

Sponge Feeding https://www.youtube.com/watch?v=pTZ211cIjX8&vl=en (2 min)

https://www.youtube.com/watch?v=pTZ211cIjX8&vl=en

Phylum CNIDARIA or COLENTRATES Example: Jelly Fish, Sea Anemone

Sometimes called Coelenterates this phylum includes organisms that are mainly marine. Cnidarians are

more complex than sponges. They have tissues

specialized to perform specific functions. Unlike Sponges

which have no symmetry, Cnidarians are radially

symmetrical. Radial Symmetry means body parts are

repeated around the central part of the body.

Cnidarians have 2 body forms: polyp -a sessile

cylindrical sac-like body or a motile bell like medusa

form. Both have a centrally located mouth surrounded

by tentacles.

Almost all Cnidarians are carnivores. They usually use

nematocysts (stinging structures) located on their

tentacles to sting or even paralyze their prey. Food is pulled into the mouth which opens into a blind gut

(sac like cavity) where it is digested. Due to their acoelomate (single opening) body plan wastes must

leave through the mouth.

Swimming Anemone https://www.youtube.com/watch?v=ysOmq71fcMk (1:30)

Like sponges Cnidarians are capable of both asexual and sexual

reproduction with many medusae members beginning life as a polyp

becoming free swimming as an adult.

Jellyfish 101: https://www.youtube.com/watch?v=9z8ujpPgUjI (3:50)

Phylum PLATYHELMINTHES, Phylum NEMATODA, Phylum ANNELIDA

Members of these 3 Phyla are commonly called worms.

These organisms are all bilaterally symmetrical

meaning only symmetrical in one direction with a front

(anterior) end and a back (posterior) end. They also

have a back (dorsal) surface and a belly (ventral)

surface. All have evolved organs to perform life

functions.

https://www.youtube.com/watch?v=ysOmq71fcMkhttps://www.youtube.com/watch?v=9z8ujpPgUjI

Platyhelminthes – Example: Planaria, Tapeworm

“Flatworms” are the simplest invertebrates that have

organs and organ systems. They have a simple brain

and nervous system that coordinates the movement of

the muscular system. This concentration of nerves in the

anterior end is called Cephalization.

Planaria are free-living carnivores. They have a pharynx

used to take in food and digest it. Waste goes out the

pharynx as well. They have eyespots to detect light.

This is the first time we see some type of nervous system.

Planaria Regeneration https://www.youtube.com/watch?v=w0QzSYQGsnA (0:30)

Tapeworms attach themselves inside the intestines and absorb the

nutrients the host takes in. Some can grow up to 50 feet in length.

Tapeworms do not have a digestive system because they are

parasitic and the organism they live in has already digested the

food so they don’t need one. This allows room for a well developed

reproductive system in the form of proglottids. Each one contains

both male and female reproductive structures.

Nematoda – example: Ascaris, Hook worm

“Roundworms” have a tubular digestive

system running through the body with a

separate mouth and anus. They get their

cylindrical shape from a fluid-filled body cavity

(pseudocoel) between the digestive tract and the body wall which acts as a hydrostatic skeleton. Most

members are parasitic, covered with a tough cuticle. Nematodes reproduce sexually with separate sexes.

Parasitic hookworms https://www.youtube.com/watch?v=44aq2A6NkUw (2:07)

Annelida – Earthworm, Leach

Annelids are known as “Segmented Worms” and as such are the

first invertebrates to show true segmentation & covering on their

digestive tract (peritoneum). The space (coelom) created by the

peritoneum allows for the development of organs. Segmentation

allows for specialization of body regions (development of body systems) & more efficient movement.

You will learn more about annelids in the Earthworm Dissection. Medicinal Leeches https://www.youtube.com/watch?v=O-0SFWPLaII (3:40)

https://www.youtube.com/watch?v=w0QzSYQGsnAhttps://www.youtube.com/watch?v=44aq2A6NkUwhttps://www.youtube.com/watch?v=O-0SFWPLaII

Phylum MOLLUSCA Example: Snails, Clams and Octopuses

The name Mollusc comes from the Latin word “mollis,” which means “soft.” Molluscs have a soft body

protected by a calcium carbonate shell. Some molluscs have an internal shell called a pen (squid). A thin

layer of tissue called the mantle covers the unsegmented body and produces the shell. The body is

usually bilaterally symmetrical with a ventral, muscular foot used for locomotion. Most Molluscs have

a head that includes eyes and an open circulatory system (the heart pumps blood through tubes which

washes over organs). Three common Classes of Molluscs are gastropods (snails), bivalves (clams,

oysters) and cephalopods (squid and octopus).

Gastropods are typically a coiled body mass tucked into a shell. Some

molluscs use a file-like tongue or radula to scrape algae off of rocks. Other

molluscs are soft bottom feeders or even carnivores.

Bivalves are clams, mussels and oysters and other

similar molluscs. They retain the body plan and are

compressed in a two-valved shell. The inner part of the

shell is lined with the mantle. There is no head or

radula. Siphons pull water over the gills for breathing

as well as filtering small food particles. If a foreign particle becomes caught between the mantle and the

body, the mantle will secrete calcium carbonate over top of it resulting in a pearl. Strong muscles are

used to keep the shell closed. Clams will use their shovel shaped foot to move and to bury themselves in

the bottom sediment.

Cephalopods include squid and octopus. They are agile swimming carnivores and have their foot divided

into arms equipped with suckers to capture prey. They have a well-developed brain & excellent vision.

Cephalopods use jet propulsion to move. The water enters through the open end of the mantle cavity

and is forced out through a muscular tube called the funnel.

Octopuses have 8 long arms & lack a

shell. They are efficient hunters & bite

with a pair of beak-like jaws. If

threatened, they can emit a dark ink

produced by the ink sac, to distract

predators.

Octopus Opens a Jar https://www.youtube.com/watch?v=9kuAiuXezIU (2:50)

https://www.youtube.com/watch?v=9kuAiuXezIU

Phylum ARTHROPODA Example: Lobster, Spider, Dragonfly

Arthropods make up the largest phylum of animals with over 1 million species occupying all habitats

on Earth. The arthropod body is bilaterally symmetrical, segmented & covered by a tough nonliving

chitinous exoskeleton. The exoskeleton provides protection for well-developed body systems but must

be shed (molted) thus limiting their size. Muscles are attached to jointed appendages like legs and

mouth parts which are

adapted for a particular

lifestyle allowing for

walking, flying or swimming.

Arthropods have an open

circulatory system and

cephalization (a concentration of sensory organs in the head region) Most arthropod species have

separate sexes. Many species have larvae that look nothing like the adult & go through metamorphosis.

This contributes to the success of the Phyla as the young do not compete with adults for food. Familiar

Classes of Arthropods are Insects (Bee), Arachnids (spiders) & Crustaceans (lobster).

Arthropod Adaptations https://www.youtube.com/watch?v=bz4ODmqbnQA (3:40)

Phylum ECHINODERMS Example: starfish, sea urchins & sand dollars

Echinodermata means “spiny-skinned”. Although sometimes the

spikes look external they are part of an endoskeleton (internal) &

are really covered with a thin layer of ciliated tissue. Not all

echinoderms have spines (ie. Sand dollars). Adults are radially

symmetrical while larvae are bilateral making them our closest

invertebrate relative. Their radial symmetry is based on five

repeating pieces as they lack a head (anterior) region. The two

sides of an echinoderm are the oral side (containing the mouth) &

the aboral side (with the anus). Echinoderms have an evertable

stomach so feed by extending the stomach outward secreting digestive enzymes to begin digestion

externally. Nutrients are then absorbed & the stomach is pulled back into the body.

Echinoderms have a water vascular system of canals attached to muscular tube feet. These water-filled

channels create hydrostatic pressure within the tube feet for movement and adhesion. The nervous

system is a simple nerve net that coordinates the movement of the tube feet and spines with the absence

of a brain. The sexes are separate in most echinoderms. Asexual reproduction is through regeneration.

An arm can produce a new organism if a piece of the central disk is intact or present.

Starfish walking & feeding https://www.shapeoflife.org/video/echinoderm-animation-sea-star-body-plan (3:50)

https://www.youtube.com/watch?v=bz4ODmqbnQAhttps://www.shapeoflife.org/video/echinoderm-animation-sea-star-body-plan